SpecSteer: Synergizing Local Context and Global Reasoning for Efficient Personalized Generation

Hang Lv, Sheng Liang, Hao Wang, Yongyue Zhang, Hongchao Gu, Wei Guo, Defu Lian, Yong Liu, Enhong Chen


Abstract
Realizing personalized intelligence faces a core dilemma: sending user history to centralized large language models raises privacy concerns, while on-device small language models lack the reasoning capacity required for high-quality generation. Our pilot study shows that purely local enhancements remain insufficient to reliably bridge this gap. We therefore propose SpecSteer, an asymmetric collaborative inference framework that synergizes private on-device context with cloud-scale reasoning. SpecSteer casts collaboration as Bayesian knowledge fusion and repurposes speculative decoding as a distributed alignment protocol, yielding a Draft–Verify–Recover pipeline: the on-device model drafts personalized sequences; the cloud validates via a ratio-based mechanism that decouples reasoning verification from private context, filtering logical flaws without accessing raw user context; upon rejection, a steering recovery injects local intent during correction. Experiments demonstrate that SpecSteer successfully closes the reasoning gap and achieves superior personalized generation performance, while delivering a 2.36 X speedup over standard baselines.
Anthology ID:
2026.emnlp-main.47
Volume:
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
EMNLP
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
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Pages:
1029–1046
Language:
URL:
https://aclanthology.org/2026.emnlp-main.47/
DOI:
Bibkey:
Cite (ACL):
Hang Lv, Sheng Liang, Hao Wang, Yongyue Zhang, Hongchao Gu, Wei Guo, Defu Lian, Yong Liu, and Enhong Chen. 2026. SpecSteer: Synergizing Local Context and Global Reasoning for Efficient Personalized Generation. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 1029–1046, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
SpecSteer: Synergizing Local Context and Global Reasoning for Efficient Personalized Generation (Lv et al., EMNLP 2026)
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PDF:
https://aclanthology.org/2026.emnlp-main.47.pdf